This invention relates to pipe grapples and, more particularly, to a device that forms a fluid-tight seal with the flange on a broken length of pipe, the grapple being lowered on to the pipe flange, driving the flange against a deformable ring within the grapple to establish a seal between the grapple and the broken pipe and lock the grapple on the flange in a fluid-tight relation in order to control flow from the broken pipe, and the like.
Pipe grapples to gain control over flow from a broken pipe proposed in the prior art have used centralizer casing segments that are pressed for frictional engagement against the outer surface of the broke pipe stem. For pipe repair purposes, these pipe grapples are not entirely satisfactory. For example, the force with which the grapple is joined to a broken section of pipe is limited to the friction force that can be applied through the centralizer segments. Accordingly, and particularly when repairing offshore oil well piping in deep water, the friction force available through the casing segments may not be sufficient to keep the grapple in place.
Clearly, there is a need for a pipe grapple that avoids this and other prior art limitations.